William Shatner: [jt.org] "You know, before I answer any more questions there's something I wanted to say. Having received all your letters over the years, and I've spoken to many of you, and some of you have traveled... y'know... hundreds of miles to be here, I'd just like to say... GET A LIFE, will you people? I mean, for crying out loud, it's just a TV show! I mean, look at you, look at the way you're dressed! You've turned an enjoyable little job, that I did as a lark for a few years, into a COLOSSAL WASTE OF TIME!"

Ugh, every thing said in that article is basically a re-hash of the hit parade of technologies that "sounded really good at the time, but don't really work". Casmir effect, Alcuberre warp drive, extra spatial dimensions, etc. are just things that sound neat, but practical applications of them are impossible, misunderstood, or just plain useless.

I want a warp drive as much as anyone, but I'm beginning to tire of hearing people keep spitting out the same concepts that anyone who can read the Wikipedia entries for them already knows are not practical or are probably not possible.

Vacuum energy may exist in some form, but the apparatus to generate any significant amount of it would probably take orders of magnitude more energy to operate. No break even. Virtual particles are a hypothesis based on the logic of the Uncertainty Principle, but even if this logic is not simply explained away at a latter point, one needs to only look at what apparatus is needed to demonstrate the Casmir effect to get an idea how you would need to scale in order to get anything out of it.

The warp drive not only requires us to somehow warp space time, but to actually survive in those conditions. There's only one known thing that combines significant warping of space time with a small area. We call those... black holes. Also, Alcuberre also acknowledged a number of problems with his drive including the fact that it wouldn't be able to see where it was going.

As for extra dimensions, besides the fact that most places I have read indicate that those dimensions are probably extremely tiny, they would probably require the Planck energy to explore, which no one knows if it is even possible to attain. So, you would spend an incredible amount of energy to be able to go from one side of a quark to another, maybe even quickly.

Or not at all, considering that a spatial dimension isn't just what's on the other side of a magic wardrobe. Either our 4 dimensions couldn't fit in the smaller ones, or we could, but we'd end up like 2-D Flatlanders walking around in a 3-D world. How could we interact with such a reality? How would it benefit us at all, even if we could survive the experience?

In the matter of dimensions, there are benefits we can glean from trying to understand if they are real and learning about them, and maybe even the Casmir effect would be good for something like generating antimatter or something. Having said that, planning a spaceship based on these ideas is like planning a ship to sail the Phogiston. It's gibberish, and what's more, its stale gibberish.

If you can travel faster than light, then you should, by our current scientific understanding (general relativity) be able to travel backward in time. If you can send a message faster than light, then you should be able to send that message back in time.

It's a bit tough to explain, and it would help to be able to give a diagram, but it has to do with the "light cone" the GP post refers to. If you can find information on a "light cone", Einstein said that anything outside of a light cone may be viewed as happening at the same time as the event at the vortex, but to people traveling at different velocities, any one of those points outside of these light cones could be viewed as having happened first.

If you can travel to an arbitrary point in space-time outside of your light cone, then you could go to a point where the past event (from your original position) is now outside the light-cone of your new position. From there, you would be able to travel to that point in space-time, which would have been firmly in the past from your original location.

Maybe someone can provide a better explanation? Meh, go read Einstein. But if you don't, then just remember "travelling faster than light" is the same as "able to go back in time".

Thanks for the informative post. The thing is, if it's a proposal to build an Alcubierre drive, there are serious problems with that [wikipedia.org]. And they're not just problems as in "that makes it hard to do," they're problems as in "it wouldn't even do what people have in mind when they imagine FTL."

Anyone who has a lot of wire laying around (like if you're into building Tesla coils) can try this experiment:Make one big loop coil with a lot of turns. Then make another coil by wrapping loops around that one. Then once that's done, do an interleaved coil over that like one of those Rodin coils [jnaudin.free.fr] over the first two. (And this design is open source and public domain because I just made it up. Have fun and hack it!) Now instead of operating this thing like a normal transformer or induction coil, you run electricity through all three coils. What you're going to be doing is trying to collapse or expand three different electromagnetic fields upon one point in space in a way that can be best described as abnormal.

Now the rest of the fun for this experiment is in figuring out what type of electricity to put into the coils and at what power levels/cycles. At most, it may have some interesting results. (See if lasers bend around it, or if objects dropped through the hole in the middle do anything funny.) And then you can come up with theory to describe whats causing the wierd stuff. At the least, it's just a waste of time and possibly some some burnt up wire. (Provided you don't get too stupid and electrocute yourself or burn the house down.) Maybe you could make some really cool dynamic art with ferro-fluid sculptures. (If you have access to ferro-fluid of some sort.) Worst case scenario is that you might accidentally make an EMP device, which may get the FCC or DHS on you.

I always wondered about Faster-then-light travel and all the muck in the universe getting in the way whilst zipping through space.

Think about it.

That galaxy might be well out of our path when that path is calculated, but where the hell will it be when we are actually passing through that area, and just how, exactly, does our mucking around with time effect our spatial relationship to other celestial bodies, especially since some of them display complex interactions with both time and space?

Wouldn't that galaxy be in a different location in space since it is in a different location in time (assuming it was moving to begin with, as Big Bang Theory suggests)? One would think we would have to map all the trajectories, and not just locations, of damn near every celestial body simply to avoid crashing into them.

But hey, since we could go forward in time, we should also be able to go backward as well, right? If that is the case, it might as well be "Full speed ahead...and pass the bong." Anything goes wrong, you just go back.

But then, I could be wrong. Or could have been...or will be...man, my head hurts.

I agree that it is way to soon to be talking about engineering designs for a warp drive as anything more than speculative curiosities. But that said, if such a drive works, it isn't time that will be warped. It is space.

The basic theory behind how that could be done was worked out in a physic's paper published in the 1990s. It requires a large source of negative energy to sustain the warp "bubble" though, and its not clear how or even if that is possible. I presume this is why "dark energy" is being brought into the picture with the proposals linked by this slashdot article. Since the understanding is that if dark energy really does exist, it has a large negative magnitude.

The other problem with that initial paper that I'm aware of (there may be others) is that the paper showed that a moving bubble in space time that gets between two locations at a speed that exceeds the speed of light can exist as a valid solution to the equations of general relativity in a universe in which negative energy exists. The paper didn't demonstrate though that such a bubble could be constructed from a region of space that didn't already have one. For such a bubble to be usable as a means of transportation, even in theory, you need to demonstrate not only that "warp bubbles" can exist, you need to also demonstrate that they can be constructed at the source, and then deconstructed at the destination.

Maybe follow-up papers have discussed those details and shown that construction/deconstruction are also theoretically possible? I haven't followed up on it. But even if they do, we still require large amounts of negative energy to do this and negative energy, if it really exists at all, is not well understood.

I'm also not clear on what kind of radiation such a bubble would give off, but it's possible it would be intense enough to fry anything inside...

It is exciting to see astrophysics beginning to point at the idea notion that negative energy might actually be real though. It means that things such as warp ships are not complete fantasy. They are way, way off though, if possible at all. We likely won't know for sure for quite a long time.:)

It was several years ago, illustrated by Larry Gonick [larrygonick.com] in his cartoon science series, "Light Elements". Same premise, same idea, but the biggest problem that was mentioned in the cartoon, has not been mentioned in this article?

You can start the compression in front of the ship, and also start the expansion behind the ship, which will get it moving.

However, once you've generated the compression/expansion wave, its self-sustaining. That brings up the problem, just how do you get the forward compression to stop??? What sort of "signal" do you send ahead of the compression wave to nullify it and allow you to stop? According to the Discover article, it "involved some sort of 'anti-gravity'.", which so far hasn't been invented yet.

So what you've got is a one-way, warp-speed trip around existence for all of eternity.

http://www.technologyreview.com/blog/arxiv/23292/Quantum setback for warp drivesInclude quantum mechanics in the calculations and faster-than-light drives become unstable

Bad news I'm afraid -- it looks as if faster-than-light travel isn't possible after all. That's the conclusion of a new study into how warp drives would behave when quantum mechanics is taken into account. "Warp drives would become rapidly unstable once superluminal speeds are reached," say Stefano Finazzi at the International School for Advanced Studies in Trieste, Italy, and a couple of friends...

Einsteins space-time says that all that will ever be is mapped out and exists, just like XY and Z. Just because you and I see chemical entropy as elapsing time doesn't mean that the dimension of time is any different from XY and Z. If you have any special insight into what time is I am sure the world would be deeply interested to hear about it. Physics doesnt have a clue what time is, all of the math in physics says that there is absolutely no difference between what happens and what happens when you look at things with time reversed. We await your deep insight. (to be frank the world needs an insight because we don't have a clue about time, theres definitely no chance of any wonder warp drive thats for sure, the human race is going to die inside the solar system and the chances of seeing people on even a single other planet in the solar system are as likely as unbridled Capitalism being the future).